1. Field of the Invention
The present invention relates to a polyol composition which is a raw material for a polyurethane resin molded article, its preparation and a polyurethane resin molded article which is produced from it by a reaction injection molding process.
2. Description of the Related Art
Various reinforcing fillers substituting glass fibers are studied so as to improve surface gloss of a polyurethane resin molded article which is prepared by a reaction injection molding process (hereinafter referred to as "RIM process") from a polyol composition containing the reinforcing filler and so as to produce the molded article with good dimensional stability. Recently, calcium sulfate fiber, mica and the like are used in addition to potassium titanate needle crystal.
In order to improve productivity of the polyurethane resin molded article produced by the RIM process, a method in which a fatty acid metal salt as an internal mold release agent is beforehand mixed with a starting polyol composition, namely "IMR" is widely employed.
Since such fatty acid metal salt has poor compatibility with the polyol, it is proposed to improve the compatibility with the polyol by combining an aliphatic amine as a compatibilizing agent with the fatty acid metal salt, as described in Japanese Patent Kohyo Publication No. 501575/1986 and Japanese Patent Kokai Publication No. 97808/1987.
However, the potassium titanate needle crystal has high hygroscopicity and it is significantly moistened during long time storage. When the moistened potassium titanate needle crystal is dispersed in a polyol composition containing an aromatic diamine and a solution of a fatty acid metal salt in an aliphatic amine, the polyol composition has an increased viscosity and can be hardly handled in a molding step. The polyurethane resin molded article produced by the RIM process from such polyol composition in which the moistened potassium titanate needle crystal is dispersed does not necessarily satisfy the mold releasing property, surface conditions of the molded article and dimensional stability.